Least Common Multiple

You can view as many worked out examples as you want. First you are shown the question. Click Show Answer to view the answer.
Click Show another Example to view another example. The best way to master mathematics is by practice. But practice requires time.
If you don't have the time to practice, you can always view many practice problems completely worked out and become good at it too.

Find the *Least Common Multiple* (LCM) of the numbers 240 and 420.

**Answer**

$240=({2}^{4})(3)(5)$

$420=({2}^{2})(3)(5)(7)$

The LCM of 240 and 420 is the product of the largest powers of each prime factor in both.

Thus the LCM of 240 and 420

$=({2}^{4})(3)(5)(7)$

$=1680$